The injection of water into subterranean oil bearing formations is a common practice for increasing the amount of oil that can be recovered. As the water flows through the formation rock it pushes oil towards the producing wells. The most common material for constructing the above ground portion of water injection systems is mild steel. To minimize corrosion of the steel, oxygen present in the injection water must be removed. However, once the oxygen is removed, an ideal environment is created for the growth of sulfate reducing bacteria.
Sulfate reducing bacteria can grow in the water as planktonic organisms, or attached to the pipe walls as sessile organisms. Bacteria which grow attached to surfaces are commonly referred to as "biofilm." Sulfate reducing bacteria growing as biofilms in water injection systems can cause several serious problems. The most serious of these problems is that of microbial induced corrosion. It is well known that sulfate reducing bacteria can cause significant damage to water injection systems by corroding deep pits and holes that can completely penetrate the pipe walls. Antimicrobial chemicals are commonly added to the water in order to control the growth of sulfate reducing bacteria. The problems caused by sulfate reducing bacteria are discussed in Biofouling in Oilfield Water Systems--A Review, J. L. Lynch and R. G. J. Edyvean, BIOFOULING 1988, Vol 1, pp. 147-162 and in Sulfate-Reducing Bacteria and the Activities in Oil Production, R. CordRuwisch, W. Kleintz, F. Widdel, Society of Petroleum Engineers 1987, SPE 13554.